scholarly journals Improving the Catalytic CO2 Reduction on Cs2AgBiBr6 by Halide Defect Engineering: A DFT Study

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2469
Author(s):  
Pengfei Chen ◽  
Yiao Huang ◽  
Zuhao Shi ◽  
Xingzhu Chen ◽  
Neng Li
Keyword(s):  
Gas Adsorption ◽  
Catalytic Reduction ◽  
Deep Level ◽  
Critical Role ◽  
Co2 Reduction ◽  
First Principles Calculation ◽  
Bandgap Energy ◽  
Practical Implementation ◽  
Co2 Conversion ◽  
Defect Engineering

Pb-free double halide perovskites have drawn immense attention in the potential photocatalytic application, due to the regulatable bandgap energy and nontoxicity. Herein, we first present a study for CO2 conversion on Pb-free halide perovskite Cs2AgBiBr6 under state-of-the-art first-principles calculation with dispersion correction. Compared with the previous CsPbBr3, the cell parameter of Cs2AgBiBr6 underwent only a small decrease of 3.69%. By investigating the adsorption of CO, CO2, NO, NO2, and catalytic reduction of CO2, we found Cs2AgBiBr6 exhibits modest adsorption ability and unsatisfied potential determining step energy of 2.68 eV in catalysis. We adopted defect engineering (Cl doping, I doping and Br-vacancy) to regulate the adsorption and CO2 reduction behavior. It is found that CO2 molecule can be chemically and preferably adsorbed on Br-vacancy doped Cs2AgBiBr6 with a negative adsorption energy of −1.16 eV. Studying the CO2 reduction paths on pure and defect modified Cs2AgBiBr6, Br-vacancy is proved to play a critical role in decreasing the potential determining step energy to 1.25 eV. Finally, we probe into the electronic properties and demonstrate Br-vacancy will not obviously promote the process of catalysis deactivation, as there is no formation of deep-level electronic states acting as carrier recombination center. Our findings reveal the process of gas adsorption and CO2 reduction on novel Pb-free Cs2AgBiBr6, and propose a potential strategy to improve the efficiency of catalytic CO2 conversion towards practical implementation.

scholarly journals Electron-Reservoir Effect on a Perylene Diimide Tethered Rhenium Bipyridine Complex for CO2 Reduction

2020 ◽  
Author(s):  
Josh D. B. Koenig ◽  
Zachary Dubrawski ◽  
Keerthan Rao ◽  
Janina Willkomm ◽  
Benjamin S. Gelfand ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Density Functional ◽  
Chemical Reduction ◽  
Critical Role ◽  
Co2 Reduction ◽  
Perylene Diimide ◽  
Co2 Conversion ◽  
Faradaic Efficiency ◽  
Molecular Catalyst ◽  
Controlled Potential

Here we report on a molecular catalyst with a built-in electron-reservoir for enhanced CO2 conversion. The synthesis and characterization of this N-annulated perylene diimide (PDI) photosensitized Re(bpy) supramolecular dyad [Re(bpy-TAz-PDI)], as well as successful electro- and photocatalytic CO2-to-CO conversion, are detailed herein. Upon electrochemical reduction in the presence of CO2 and a proton source, Re(bpy-TAz-PDI) exhibited significant current enhancement, where the onset of electrocatalytic CO2 reduction for Re(bpy-TAz-PDI) occurred at a much less negative potential than standard Re(bpy) complexes. At an applied potential of -1.8 V vs. Fc+/0, 400 mV lower than the benchmark Re(dmbpy) catalyst, Re(bpy-TAz-PDI) was able to achieve the same catalytic activity (TONco = 24) and Faradaic efficiency (FE = 92 %) during controlled potential electrolysis (CPE) experiments. Through a combination of UV-visible-nearIR spectroelectrochemistry (SEC), FTIR SEC, and chemical reduction experiments, it was shown that the PDI-moiety served as an electron-reservoir for Re(bpy), thereby allowing catalytic activity at lower overpotentials. Density functional theory (DFT) studies probing the optimized geometries, frontier molecular orbitals, and spin-densities of various catalytic intermediates revealed that the geometric configuration of PDI, relative to the Re(bpy)-moiety, plays a critical role in accessing electrons from the electron-reservoir. The near identical performance of Re(bpy-TAz-PDI) at lower overpotentials relative to the benchmark Re(dmbpy) catalyst highlights the utility of organic chromophore electron-reservoirs as a method for lowering the required overpotential for CO2 conversion. <br>

scholarly journals Electron-Reservoir Effect on a Perylene Diimide Tethered Rhenium Bipyridine Complex for CO2 Reduction

2020 ◽  
Author(s):  
Josh D. B. Koenig ◽  
Zachary Dubrawski ◽  
Keerthan Rao ◽  
Janina Willkomm ◽  
Benjamin S. Gelfand ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Density Functional ◽  
Chemical Reduction ◽  
Critical Role ◽  
Co2 Reduction ◽  
Perylene Diimide ◽  
Co2 Conversion ◽  
Faradaic Efficiency ◽  
Molecular Catalyst ◽  
Controlled Potential

Here we report on a molecular catalyst with a built-in electron-reservoir for enhanced CO2 conversion. The synthesis and characterization of this N-annulated perylene diimide (PDI) photosensitized Re(bpy) supramolecular dyad [Re(bpy-TAz-PDI)], as well as successful electro- and photocatalytic CO2-to-CO conversion, are detailed herein. Upon electrochemical reduction in the presence of CO2 and a proton source, Re(bpy-TAz-PDI) exhibited significant current enhancement, where the onset of electrocatalytic CO2 reduction for Re(bpy-TAz-PDI) occurred at a much less negative potential than standard Re(bpy) complexes. At an applied potential of -1.8 V vs. Fc+/0, 400 mV lower than the benchmark Re(dmbpy) catalyst, Re(bpy-TAz-PDI) was able to achieve the same catalytic activity (TONco = 24) and Faradaic efficiency (FE = 92 %) during controlled potential electrolysis (CPE) experiments. Through a combination of UV-visible-nearIR spectroelectrochemistry (SEC), FTIR SEC, and chemical reduction experiments, it was shown that the PDI-moiety served as an electron-reservoir for Re(bpy), thereby allowing catalytic activity at lower overpotentials. Density functional theory (DFT) studies probing the optimized geometries, frontier molecular orbitals, and spin-densities of various catalytic intermediates revealed that the geometric configuration of PDI, relative to the Re(bpy)-moiety, plays a critical role in accessing electrons from the electron-reservoir. The near identical performance of Re(bpy-TAz-PDI) at lower overpotentials relative to the benchmark Re(dmbpy) catalyst highlights the utility of organic chromophore electron-reservoirs as a method for lowering the required overpotential for CO2 conversion. <br>

scholarly journals Investigation of Gas Diffusion Electrode Systems for the Electrochemical CO2 Conversion

Catalysts ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 482
Author(s):  
Hilmar Guzmán ◽  
Federica Zammillo ◽  
Daniela Roldán ◽  
Camilla Galletti ◽  
Nunzio Russo ◽  
...  
Keyword(s):  
Carbon Capture ◽  
Active Sites ◽  
Co2 Reduction ◽  
Gas Diffusion ◽  
Gas Diffusion Electrode ◽  
Catalyst Loading ◽  
Co2 Conversion ◽  
Atmospheric Conditions ◽  
Electrochemical Co2 Reduction ◽  
Liquid Products

Electrochemical CO2 reduction is a promising carbon capture and utilisation technology. Herein, a continuous flow gas diffusion electrode (GDE)-cell configuration has been studied to convert CO2 via electrochemical reduction under atmospheric conditions. To this purpose, Cu-based electrocatalysts immobilised on a porous and conductive GDE have been tested. Many system variables have been evaluated to find the most promising conditions able to lead to increased production of CO2 reduction liquid products, specifically: applied potentials, catalyst loading, Nafion content, KHCO3 electrolyte concentration, and the presence of metal oxides, like ZnO or/and Al2O3. In particular, the CO productivity increased at the lowest Nafion content of 15%, leading to syngas with an H2/CO ratio of ~1. Meanwhile, at the highest Nafion content (45%), C2+ products formation has been increased, and the CO selectivity has been decreased by 80%. The reported results revealed that the liquid crossover through the GDE highly impacts CO2 diffusion to the catalyst active sites, thus reducing the CO2 conversion efficiency. Through mathematical modelling, it has been confirmed that the increase of the local pH, coupled to the electrode-wetting, promotes the formation of bicarbonate species that deactivate the catalysts surface, hindering the mechanisms for the C2+ liquid products generation. These results want to shine the spotlight on kinetics and transport limitations, shifting the focus from catalytic activity of materials to other involved factors.

Water nanodomain for efficient photocatalytic CO2 reduction to CO

2021 ◽  
Author(s):  
Gang Chen ◽  
Xiuyan Cheng ◽  
Jianling Zhang ◽  
Qiang Wan ◽  
Ran Duan ◽  
...  
Keyword(s):  
Co2 Reduction ◽  
Evolution Rate ◽  
Co2 Conversion ◽  
Photocatalytic Co2 Conversion

Herein we propose the utilization of nanosized water domain for photocatalytic CO2 conversion, by which CO2 can be efficiently reduced to CO with CO evolution rate of 682 µmol g-1...

scholarly journals Heterogeneous Electrocatalysts for CO2 Reduction to Value Added Products

2021 ◽  
Author(s):  
M. Amin Farkhondehfal ◽  
Juqin Zeng
Keyword(s):  
Fossil Fuels ◽  
Greenhouse Gas Emission ◽  
Global Climate ◽  
Renewable Energy Sources ◽  
Critical Role ◽  
Co2 Reduction ◽  
Value Added ◽  
Reduction Reaction ◽  
Added Value ◽  
Global Climate Changes

The CO2 that comes from the use of fossil fuels accounts for about 65% of the global greenhouse gas emission, and it plays a critical role in global climate changes. Among the different strategies that have been considered to address the storage and reutilization of CO2, the transformation of CO2 into chemicals and fuels with a high added-value has been considered a winning approach. This transformation is able to reduce the carbon emission and induce a “fuel switching” that exploits renewable energy sources. The aim of this chapter is to categorize different heterogeneous electrocatalysts which are being used for CO2 reduction, based on the desired products of the above mentioned reactions: from formic acid and carbon monoxide to methanol and ethanol and other possible by products. Moreover, a brief description of the kinetic and mechanism of the CO2 reduction reaction) and pathways toward different products have been discussed.

Enhancing CO2 photoreduction over ZIF-based reticular materials by morphology control of Au plasmonic nanoparticles

2022 ◽  
Author(s):  
Jorge Becerra ◽  
Vishnu Nair Gopalakrishnan ◽  
Toan-Anh Quach ◽  
Trong-On Do
Keyword(s):  
Band Structure ◽  
Energy Band ◽  
Co2 Reduction ◽  
Morphology Control ◽  
Energy Band Structure ◽  
Plasmonic Nanoparticles ◽  
Co2 Conversion ◽  
Zeolitic Imidazolate Frameworks ◽  
Co2 Photoreduction ◽  
Proper Energy

Zeolitic imidazolate frameworks (ZIFs) are promising photocatalysts for CO2 reduction due to their proper energy band structure and crystalline properties. However, CO2 conversion is still low due to the serious...

Critical role of water stability in metal–organic frameworks and advanced modification strategies for the extension of their applicability

2020 ◽  
Vol 7 (5) ◽  
pp. 1319-1347 ◽  
Author(s):  
Botao Liu ◽  
Kumar Vikrant ◽  
Ki-Hyun Kim ◽  
Vanish Kumar ◽  
Suresh Kumar Kailasa
Keyword(s):  
Drug Delivery ◽  
Water Purification ◽  
Gas Adsorption ◽  
Critical Role ◽  
Metal Organic Frameworks ◽  
Water Stability ◽  
Metal Organic

Metal–organic frameworks (MOFs) are well known for their versatile applications in diverse fields (e.g., gas adsorption, water purification, sensing, drug delivery, and catalysis).

Gas adsorption on the pristine monolayer GeP3: A first-principles calculation

Vacuum ◽  
2019 ◽  
Vol 164 ◽  
pp. 181-185 ◽  
Author(s):  
Binwei Tian ◽  
Taohua Huang ◽  
Jiyuan Guo ◽  
Huabing Shu ◽  
Ying Wang ◽  
...  
Keyword(s):  
First Principles ◽  
Gas Adsorption ◽  
First Principles Calculation
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